"You've not been on holiday unless you've been on a ferry" was a comment overheard on Tiree a few years ago and I can't argue with the sentiment as most of my favourite places require a ferry trip to reach and, as an added bonus, no passport since they are all in the UK.
My early childhood holidays were spent camping on Guernsey which was reached by a ferry crossing from Weymouth. We travelled on the boat train from Waterloo and I was fascinated by the final stage of the train journey into the docks as it involved the train going down the middle of the road between the houses! When my father bought his first car, a Morris Traveller, we were able to take all our camping gear with us instead of sending it on ahead in a large wooden chest. This was in the days before Ro-Ro ferries and the car had to be lifted into the ship's hold by crane, dangling rather precariously on nets placed under the wheels. Not long after that the first Ro-Ro ferry was introduced and not only was it easier to get on and off but it also cut the ferry crossing time to less than four and a half hours.